Fusion reactors, if achieved, promise to bring the world near-limitless clean energy, tapping into the processes of the sun and stars to generate power here on Earth.

As scientists around the world work toward creating a functional fusion reactor, a remarkable video shared on YouTube has revealed a look at what goes on inside one of these massive devices.

High-speed footage from an experimental facility in Prague shows the dramatic formation of the plasma column inside the tokamak – the magnetic confinement system at the heart of the reactor.

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As scientists around the world work toward creating a functional fusion reactor, a remarkable video has revealed a look at what goes on inside one of these massive devices. High-speed footage shows the dramatic formation of the plasma column inside the tokamak

HOW DOES FUSION POWER WORK?

Fusion involves placing hydrogen atoms under high heat and pressure until they fuse into helium atoms.

When deuterium and tritium nuclei - which can be found in hydrogen - fuse, they form a helium nucleus, a neutron and a lot of energy.

This is down by heating the fuel to temperatures in excess of 150 million°C, forming a hot plasma.

Strong magnetic fields are used to keep the plasma away from the walls so that it doesn't cool down and lost it energy potential.

These are produced by superconducting coils surrounding the vessel, and by an electrical current driven through the plasma.

For energy production. plasma has to be confined for a sufficiently long period for fusion to occur.

The footage shot last year surfaced on Reddit this week, as recent breakthroughs have reignited hopes for fusion power.

Inside the tokamak at the Institute of Plasma Physics, flashes of light can be seen growing brighter and brighter as the plasma column forms and refills.

It all takes place in under two seconds – but, shot at a staggering 1,000-20,000 frames per second, the footage lasts about a minute long.

Then, it comes to a dramatic conclusion in a burst of light, followed suddenly by darkness.

‘On 20th January, 2016, the first high-speed colour videos from the COMPASS tokamak discharges were recorded by a new fast CMOS camera of the Photron Mini UX100 type,’ according to the Institute of Plasma Physics IPP.

‘In ohmically heated plasmas in a divertor configuration and deuterium as a working gas, the videos of 1000-20000 frames per second revealed formation of the plasma column, its shaping and refilling by the gas puffing, and also a plasma-wall interaction resulting in dust particles propagating across the vacuum vessel of the tokamak.’

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The Compass Tokamak is relatively small, according to the Intstitute of Plasma Physics, and its plasmas are only about a tenth the size of the plasmas of ITER – the world’s largest fusion experiment.

In recent months, there have been several breakthroughs promising to bring fusion power closer to reality than ever before.

This past April, Britain’s newest fusion reactor fired up, and experts claimed it could even provide clean energy to the UK’s national grid by 2030.

Known as Tokamak ST40, it’s expected to reach a temperature of 100 million centigrade as soon as next year.

Inside the tokamak at the Institute of Plasma Physics, flashes of light can be seen growing brighter and brighter as the plasma column forms and refills. Then, it comes to a dramatic conclusion in a burst of light, followed suddenly by darkness

The Compass Tokamak is relatively small, according to the Intstitute of Plasma Physics, and its plasmas are only about a tenth the size of the plasmas of ITER (illustrated above) – the world’s largest fusion experiment

And, just this month, researchers discovered a way to slam the brakes on ‘runaway electrons’ – one of the major challenges to the technology.

These so-called runaway electrons are particles of extremely high energy that can accelerate without warning inside a fusion reactor and destroy the walls of the machine.

The plasma physicists from Chalmers University of Technology found that heavy ions could be used to slow down the electrons in the tokamak.

WHAT IS A TOKAMAK?

The tokamak is the most developed magnetic confinement system and is the basis for the design of fusion reactors.

Plasma is contained in a vacuum vessel, which is then heated by driving a current through it.

A combination of two sets of magnetic coils creates a field in both vertical and horizontal directions, acting as a magnetic 'cage' to hold and shape the plasma.

The heating provided by the plasma current supplies a third of the 100 million°C temperature required to make fusion occur.

The tokamak is the most developed magnetic confinement system and is the basis for the design of fusion reactors. An illustration of the massive ITER device is shown

Additional plasma heating is provided when neutral hydrogen atoms are injected at high speed into the plasma, ionized and trapped by the magnetic field.

As they are slowed down, they transfer their energy to the plasma and heat it.

High-frequency currents are also induced in the plasma by external coils.

The frequencies are chosen to match regions where the energy absorption is very high.

In this way, large amounts of power may be transferred to the plasma.

Neon or argon, for example, in the form of gas or pellets, present something for the high-energy electrons to collide with.

And, with each collision, they encounter resistance and lose speed.

According to their new model, it’s possible to predict the energy of these runaway electrons, and determine how it will change.

The breathtaking footage reveals a look at what goes on inside the COMPASS tokamak at the Institute of Plasma Physics in Prague

‘When we can effectively decelerate runaway electrons, we are one step closer to a functional fusion reactor,’ said doctoral student Linnea Hesslow.

‘Considering there are so few options for solving the world’s growing energy needs in a sustainable way, fusion energy is incredibly exciting since it takes its fuel from ordinary seawater.’

Scientists around the world have been working hard to bring a functional fusion reactor to life for the past fifty years.